Albumin is emerging as a versatile drug carrier in a number of applications in cancer nanomedicine. We coupled albumin with a peptide containing the isoDGR motif, a ligand of integrins expressed in tumor vessels, to enhance its tumor homing properties. To this aim, we designed various head-to-tail-cyclized isoDGR peptides and analyzed their integrin binding properties. We have identified a peptide (c(CGisoDGRG)) (SEQ ID NO:1) that, after coupling to human serum albumin, has a very good selectivity for αvβ3 and αvβ5, two integrins overexpressed in the tumor vasculature. In vitro and in vivo studies showed that isoDGR-tagged albumin binds to endothelial cells, inhibits their adhesion properties, homes in on tumor vessels and inhibits tumor growth, with no evidence of toxicity. Furthermore, coupling c(CGisoDGRG) (SEQ ID NO:1) to albumin/paclitaxel nanoparticles improved their cytotoxic activity against αvβ3-positive endothelial cells, but not against αvβ3-negative cells. These results suggest that isoDGR-tagged albumin is a new vascular targeting agent. Because of its good selectivity for tumor vessels and its inherent anticancer activity isoDGR-tagged albumin might be exploited as a carrier for the preparation of a wide range of tumor vasculature-selective drugs and nanoparticles for cancer therapy and diagnosis.